1. Field of the Invention
The present invention relates to an apparatus for conveying a photographic film, in which the photographic film includes perforations provided in advance at predetermined intervals and at which a predetermined number of perforations is provided with respect to the area of one image frame. Respective images of the photographic film are photographed so that relative positions between the perforation and the image are constant.
2. Description of the Related Art
Conventionally, in a 135 size negative film or the like, perforations (rectangular holes) are provided at a predetermined pitch in advance. When the negative film is loaded in a camera, the perforations engage with a sprocket or the like so that driving force is applied to the negative film. Further, the perforations correspond to a contact or the like provided at the camera and serve to indicate whether the negative film is accurately conveyed. When the film is conveyed by the camera, the initial positions, i.e., the position in which the film is loaded, varies. As a result, the relative positions between the perforation and the photographed image frame are not constant.
In a case in which the photographic film which was photographed is, for example, print processed by a printing device, it is necessary to position the respective image frames at a printing position.
In this case, there is no mark (indicator) which specifies the image frame. Accordingly, it is necessary to have a complicated control in which an edge of the first image frame is detected in accordance with density difference between the first image frame and a base portion. On the basis of the results of edge detection, a predetermined amount of frames are forwarded and positioned at the printing position.
However, in the aforementioned frame forwarding control, when the negative film is loaded in the camera, even if the frame is "advanced without exposure" (i.e., advanced so as to skip a frame or frames which are not to be exposed) for some reason and one frame area is unexposed, for example, the unexposed portion is positioned at the printing position. Then, the printing operation, and thereafter, the verifying operation are effected.
In this way, normal processing, such as print processing or the like, is effected in the portion (area) in which the processing is not required. Consequently, materials such as a printing material (e.g., a photographic printing paper) and hours of operation are wasted.
In recent years, it has been proposed that information can be magnetically recorded onto the negative film. In such a negative film, the perforations are provided in advance at predetermined intervals and the predetermined number of perforations are provided with respect to one image frame. As a result, the film is photographed so that the relative positions between the perforation and the image frame are constant.
Even in such a negative film, if the frame is advanced without exposure for some reason, the image is unexposed and the similar drawback arises.
Further, when the photographic film which was photographed is, for example, print processed by the printing device, the negative film may be separated from a cartridge called patrone (the patrone is discharged when the negative film is separated therefrom). In this case, a single negative film is conveyed or a plurality of connected negative films are conveyed, and the image frames are forwarded so as to be successively positioned at the printing position.
The negative film is conveyed in one direction. The negative film, in which print processing thereof has been completed, is conveyed out of the side opposite the side, into which the negative film is conveyed, with respect to the printing position. Moreover, the negative film, in which print processing thereof has been completed, is cut every predetermined number of frames (usually six frames). The film is then accommodated within a negative sheet with the film cut into piece negatives (a strip of negative film containing several frames), and thereafter, is returned to a customer.
Here, in recent years, film has been proposed in which a magnetic recording layer is provided, and information regarding the time at which the film is photographed, information regarding the time at which the film is print processed, and the like are recorded onto the magnetic recording layer. Even if the film has been developed and print processed, such photographic film is not cut every predetermined number of frames so as to prevent separation of the magnetic recording layer. In addition, the film is developed and printed without being separated from the cartridge, and thereafter, is rewound in the original cartridge. Consequently, when the film is returned to the customer, it has been considered in which the film is returned in a state in which the film is accommodated within the cartridge.
As a result, the magnetic recording layer is not separated. Further, it is possible to prevent a drawback in which the magnetic recording layer is scratched and the information thereon cannot be read or written.
The cartridge and the inner end portion of the photographic film which was wound in the cartridge in layers are temporarily engaged so that, as occasion demands, the photographic film can be separated from the cartridge. This is because in a case in which a large amount of photographic films are processed, it is more efficient to connect and process a plurality of photographic films than to process the films separately.
However, in a case in which the photographic film is print processed in a state in which the film is not separated from the cartridge, when the position of the last frame is not specified, the film is successively conveyed in the withdrawing direction of the photographic film. As a result, excessive force is applied to the temporarily-engaged portion between the rear end portion of the photographic film and the cartridge so as to-damage the temporarily-engaged portion.
With the aforementioned in view, an object of the present invention is to obtain an apparatus for conveying a photographic film, in which the existence of the image frame at a position onto which the image frame is to be recorded can be recognized in advance so that the unnecessary positioning of the image frame is eliminated, and the waste of material and time at the respective processes for operation can be omitted.
Another object of the present invention is to obtain an apparatus for conveying a photographic film, in which the position of the image frame can be easily searched, and the film can be reliably conveyed to the predetermined position while the image frame is positioned.
Still another object of the present invention is to obtain an apparatus for conveying a photographic film, in which, in a case in which the photographic film is withdrawn from the cartridge without being separated therefrom, the position onto which the last image frame is to be recorded is recognized, the withdrawal of the last image frame beyond the predetermined position is prohibited, and the damage at the engaging portion between the photographic film and the cartridge can be prevented.